72 The Food of Some British Wild Birds. 



'"-i 



Beal (15) estimated the amount of weed seed eaten by various 

 sparrows during their winter sojourn in the State of Iowa at about 

 875 tons. 



2. Distribution of Weed Seeds. 



We have already seen that the food of many wild birds consists, 

 for a considerable part of he year, of the seeds of weeds and other 

 plants, and it has, all too hastily, been assumed that such seeds 

 are destroyed, either before being swallowed or in their passage 

 through the intestinal canal. Such, however, is not always the 

 case. 



Judd (74, p. 49) writing of the relation of sparrows to agricul- 

 ture, states: "During January and February, 1900, a series of 

 experiments was carried out to ascertain how far sparrows are 

 responsible for the dissemination of the seeds upon which they 

 subsist. The only birds available for these experiments were seven 

 English sparrows, but the conclusions reached are, in a measure, 

 applicable to all sparrows. The birds were fed on seeds <of different 

 weeds, and all their droppings were examined to ascertain the 

 condition in which the seeds were voided. The seeds of climbing 

 false buckwheat and ragweed were found to be thoroughly pulver- 

 ized, although quite a number of small fragments of the black, 

 shiny coats of the former were found in the droppings. This result 

 was expected, since the birds crack these seeds before swallowing 

 them. The seeds of lamb's-quarters and amaranth were next tried. 

 These, because of their small size and hard structure, it was 

 supposed, would be swallowed whole, and would partially escape 

 destruction in their passage through the bird's digestive tract. 

 But such proved not to be the case. The birds cracked them as 

 they had the others. Halves of seed shells were found in the seed 

 cup, and many broken smaller pieces ; and the droppings of the 

 birds showed no whole seeds, although some few empty split seeds 

 with the two half-shells clinging together were found. Usually 

 only the finely pulverized dust of the seed coats was found in the 

 faeces. When the sparrows were not under experimentation they 

 were fed chiefly on millet, the grain of which is inclosed by two 

 corrugated siliceous glumes. These were similarly removed by the 

 birds. No whole seeds were found in the dung, and only an occa- 

 sional small piece of one of the glumes. The closely related seeds 

 of pigeon-grass (Choetocloa viridis) are inclosed by much stronger 

 glumes, but when these were fed to the birds the cracking of the 

 grain and the removing of the glumes appeared to be just as 

 complete as in the case of the millet, and seemed as certainly to 

 preclude any possibility of subsequent germination. 



"Some experiments were made with the seeds of crab-grass 

 (Panicum sanguined*). A well-known firm of seedsmen suggested to 



